Security Experts:

65 Million Users Affected by Tumblr Breach

The data breach disclosed earlier this month by the Yahoo-owned microblogging platform Tumblr affects 65 million users.

On May 12, Tumblr warned that a third party gained access to the email addresses and hashed passwords of Tumblr users who had registered accounts up until early 2013, before the company was acquired by Yahoo. Tumblr said it had not found any evidence that the leaked information was used to access accounts, but it reset the passwords of affected customers as a precaution.

Tumblr refused to say how many users had been affected by the breach, but it turns out that it’s a significant number. An individual using the online moniker “peace_of_mind” has been offering information associated with 50 million Tumblr accounts on a darknet website called “The Real Deal” for the price of 0.4255 Bitcoin (roughly $225).

Australian security researcher Troy Hunt has analyzed the data and found a total of 65,469,298 records. The information has been added to Hunt’s “Have I Been Pwned” service to allow users to check if they are affected. Hunt reported that 20 percent of the accounts were already present in Have I Been Pwned.

People who have signed up for the service will also be notified via email. It’s worth noting that some users complained about not being notified by Tumblr directly after the breach was first disclosed.

Vice’s Motherboard reported that the information is being sold by “peace_of_mind” for a relatively small amount of money because the passwords are hashed using SHA1 and salted, which makes them difficult to crack.

The same hacker is also selling millions of records associated with the users of several other popular services, such as LinkedIn (167 million accounts sold for 2 Bitcoin), the adult dating website Fling.com (40 million accounts sold for 0.58 Bitcoin), and the social networking website Myspace (360 million accounts sold for 6 Bitcoin).

The LinkedIn data was leaked as a result of the 2012 data breach. Until “peace_of_mind” put the information up for sale, it was believed that the incident only affected 6.5 million accounts.

Reddit users are also affected by these recent mega leaks - the social news website said it observed an uptick in account takeovers by malicious third parties. The company reported last week that it had reset the passwords of roughly 100,000 accounts over a two-week period.

Related ReadingLinkedIn Breach: How a 6.5M Hole Could Sink a 160M Ship 

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Eduard Kovacs (@EduardKovacs) is a contributing editor at SecurityWeek. He worked as a high school IT teacher for two years before starting a career in journalism as Softpedia’s security news reporter. Eduard holds a bachelor’s degree in industrial informatics and a master’s degree in computer techniques applied in electrical engineering.